To elucidate the exact cause of this antiviral ability, scientists cultured vesicles with viruses and imaged them under a microscope. They found that viruses attach to receptors on the surface of vesicles, trapping them and preventing them from infecting cells. In other words, the vesicles functioned as a kind of decoy. “Because vesicles have the same receptors as cells, most viruses bind to vesicles and are killed before they reach the cell,” says Briar.
In addition, scientists also found that stimulated vesicles contained more microRNAs (small strands of RNA), which were previously known to have antiviral activity.
Finally, the scientists wanted to see how small temperature changes affected the quality and quantity of secreted vesicles. They used small pieces of mucosal tissue extracted from a small number of patients’ noses and put those small pieces of tissue, known as explants, into cell culture. , stimulated tissues to upregulate TLR3 and collected secreted vesicles.
They found that colds caused a 42 percent reduction in the ability of tissues to secrete vesicles, and those vesicles had 77 percent fewer receptors that allow them to bind and neutralize viruses. “Even a five-degree descent for 15 minutes really made a dramatic difference,” says Amiji.
Noam Cohen, an otolaryngologist at the University of Pennsylvania, said the study sheds light on how the virus spreads more easily in cold weather. (Cohen wasn’t involved in the study, but had mentored Bleier when he was a medical student.) “They optimized the low temperature to replicate.”
Jennifer Bomberger, a microbiologist and immunologist at Dartmouth College, said one of the interesting things about the study was that “the vesicles weren’t just immune education,” they weren’t just carrying instructions for the immune system. I’m here. Instead, she continues, “they were actually performing some of the real antiviral effects by binding to the virus.” By looking at the mucus of an actual infected patient, they say, it may provide additional insight into how these vesicles work.
The behavior of these vesicles is not the only reason why upper respiratory tract infections peak in winter. Previous research has shown that cold temperatures also reduce the work of the immune system’s antiviral molecules called interferons. Viruses also tend to spread when people move indoors. Social distancing during the pandemic may also be weakening the buildup of immunity against the viruses that cause influenza and RSV, both of which are part of the “triple epidemic” that emerged this winter.
Still, Amiji says understanding exactly how vesicles change could lead to interesting treatment ideas. He visualizes it as “hacking” a vesicle’s “murmurings.” “How can we increase the content of these antiviral mRNAs or other molecules to have a positive effect?” he asks.
In light of the Covid-19 pandemic, researchers note that there are already practical, real-world ways to protect your nose in cold weather. It’s masking. The nose can remain snug and comfortable under the mask. This can be attested to by anyone who wears glasses whose lenses fog up from warm breath. “Wearing a mask may have a dual protective role,” Briar says. “People certainly prevent physical inhalation of the substance. [viral] Not only by the particles, but also by maintaining the local temperature at least at a relatively higher level than the external environment. “
And here’s another idea to consider. Perhaps it’s time to go on vacation somewhere warm.
